1. Field of the Invention
The invention relates to improvements in the underground piping employed with lawn sprinkler systems. In particular, the invention relates to the interconnecting line coupling the spinkler head to the water supply line. In particular, the invention relates to the use of a performed flexible interconnection line which provides a flexible coupling between sprinkler head and the water supply line and is shaped such that the ditching required to incorporate the piping within the ground will be of minimal width and depth.
2. Prior Art
Lawn sprinkler systems generally comprise an underground water supply line to which sprinkler heads are connected by means of nipples or risers. Preferably, only the upper surface of the sprinkler head will rise to or slightly above the surface of the ground in which the sprinkler system is installed. When lawn maintenance equipment passes over, and makes contact with, the sprinkler heads a downward force is directed through the spinkler head and riser to the water supply line. In addition, over a period of time environmental effects, temperature variations and precipitation, will cause the sprinkler heads to rise upward above the surface of the ground where they become subject to the affects of shocking lateral forces such as might occur when stubbed by a person's foot.
In any event, forces applied to the sprinkler head are transferred through the nipple to the water supply line. As a result, damage is frequently encountered either at the junction of the sprinkler head to the nipple, the nipple with the supply line or the nipple itself. To reduce the effects of such shock caused damage, the prior art has resorted to the use of flexible nipples. In general, these nipples consist of a length of flexible line having threaded connectors at each end. When such a flexible nipple is utilized, it is, of course, necessary that the flexible section be of sufficient length to allow the nipple to flex under stress. Because of the necessary length to permit flexure, the flexible nipple imposes adverse dimensional changes on the trench which must be dug into the earth in order to install the water supply line. If the flexible nipple extends outwardly to the side of the water supply line, the trench must be increased in width over that of a lawn sprinkling system utilizing a short but rigid nipple. If the flexible nipple rises vertically from the water supply line, the trench must be dug deeper than that which is necessary when short but rigid nipples are employed.
Examples of such flexible nipples as found in the prior art are disclosed by King in U.S. Pat. No. 3,759,445, issued Sep. 18 1973; and in the U.S. Patent issued to Bjurman, U.S. Pat. No. 4,314,717, Feb. 9, 1982.
It is an object of the present invention to provide a preformed, flexible line to be used as a nipple or interconnector between lawn sprinkler head and water supply line. However, the invention will impose no adverse dimensional requirements on the trenching employed in installing a lawn sprinkler system utilizing the invention.
It is further objective of the invention to eliminate the necessity of expending money and labor to purchase and install threaded couplings on the flexible, preformed interconnection line.